Exam 18: Descriptive Statistics

Let us suppose we are predicting the score on a training posttest from the number of years of education and the score on an aptitude test given before training. Here is the regression equation: Y = 25 + .5X₁ +10X₂, Where X₁ = years of education and X₂ = aptitude test score. Which of the following are true about this equation?

Which will be the best measure of central tendency for these data?

Charlie was looking at the variability of his data. The range for his sample was 150. The variance for his sample was 49. What is the standard deviation for the sample?

Sally wants to graphically represent her data from her study. She collected data on the number of hours her students spent on homework every day of the week. What pictorial representation should she use for her study?

Multiple regression examines:

To calculate a mean, you add up the scores and then divide the sum by the number of scores that you have.

A problem with the mode is that:

Regression analysis involves:

A percentile rank tells you:

Which will be the best measure of central tendency for these data?

"Skewed" means that a distribution is not symmetrical.

You take the ACT and have a percentile rank of 34. Your percentile rank shows your standing relative to a reference or norming group.

Below are z scores for four people who took a test. Which one scored the highest? John -2.9, Samantha +2.1, Sally +0.1, and Joshua +1.0

Below is a regression equation predicting children's math achievement from their parents' education level (years of education). Y = 1 + 2x, Where x is the number of years of parental education. What would be the predicted score for a child whose parents had 12 years of education?

Describe the similarities of and differences between frequency distributions and grouped frequency distributions.

The two subfields in descriptive statistics are estimation and hypothesis testing.

A researcher gathered the following set of data: 54, 56, 56, 56, 57, 57, 58, 58, 59, 59. Which term would best describe these data?

The relationship between two quantitative variables is typically represented with a:

The plus or minus sign before a z score tells you:

Helen has used vertical bars to represent her categorical data. She has created a: